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Several factors cause the degradation of cellulose that the most important factor of them is Acidic Hydrolysis. Many historical books are gradually destroyed due to acidic hydrolysis and reduction of the degree of polymerization of cellulose. So deacidification and strengthening treatments for valuable old papers to stop these processes are necessary. Since the paper is a good substrate for growth of some destroying fungi, applying a suitable restoration treatment to stop or delay the growth of these destroying microorganisms - in addition of increasing the pH and preparing alkaline conditions for paper- has been considered. In this study, in order to deacidification and strengthening of paper, with different combinations of Nano Calcium hydroxide, Nano Hydroxyapatite, Nano cellulose and Nano Chitosan in an alcoholic solvent )ethanol), a Nano coat was applied on the surface of the sample paper. For study the anti-fungal properties, biologic aging was done on treated paper with Aspergillus fungi. For this purpose, after preparing culture medium, treated papers in separate petri dishes were inoculated and after incubation period, the amount of fungal growth was studied. Also, tensile strength test was done on treated samples. Results showed that diacidifation treatments by preparing an alkaline condition increased the pH of paper and the paper treated with a complex of Nano calcium hydroxide and Nano chitosan, and also treated samples with Nano Hydroxyapatite had lowest fungal contamination. Treated Papers with Nano calcium hydroxide and Nano chitosan showed better tensile strength properties and applying Nano cellulose in treatments improved the tensile strength of treated papers although had the less anti-fungal resistance.

Cleaner production process is an environmentally friendly approach that attempts to reduce waste and energy consumption then reduce environmental pollutions of industrial processes to provide the possibility of sustainable production in industrial units. To achieve this goal and alignment with cleaner production strategies, paper industries should consider reducing wastes of production processes and irregular consumption of energy as a priority in their programs. In this research Analytic Hierarchy Process has been applied and a three level hierarchy model was structured to facilitate the cleaner production process in Latif paper products firm. Using a literature review and field study, the proposed model provided a framework for cleaner production implementation in the firm. Results showed priorities of the main criteria of cleaner production are process change, product modification, implementation of preventive maintenance system, resititution and man force capitals respectively. Process change criterion allocated 40 percent of the total weighing value and has the highest priority in implementation of cleaner production strategy. Existence of industrial automation and its technology level which is a sub criterion of process change has the highest priority among 31 sub criteria. Also some of higher priority sub criteria such as use of higher quality inclusion and implementation of calibration system are related to process change. Therefore, to achieve cleaner production goals and implementation of its strategic objectives it is necessary to pay more attention to this criterion. Inconsistency ratio of the research is 0.06 which indicates the results are compatible. The results of this research can be used to accelerate the implementation of cleaner production process in Iran’s pulp and paper industry.

This study was carried out in order to investigate the effects of different types of resins and also their mixtures on the impregnated paper properties. In this regard, pure urea resin (100%), mixture of melamine and urea resins with various combinations (60/40 and 70/30 and 50/50), mixture of nano-fiber cellulose ratios of 1, 2 and 3 percent with urea resin and pure PVA (100%) were used to impregnate of newsprint basic paper of Mazandaran wood and paper industries. Immersion of samples in the impregnation step were done in two time of 5 and 10 seconds. Next, melamine resin was used for surface coating and then absorption of resin in the impregnation and coating process measured. Results showed that in the impregnation step with pure urea (100%), in the respect of absorption rate and surface properties of melamine paper, the best time of impregnation was obtained 10 seconds. In the combined treatment, adding up to 30% melamine to urea resin, as impregnation step resin, offers better properties in terms of stain resistance, cigarette resistance, resistance to cracking and resistance to hot water steam for impregnatedmade paper. By adding nanocellulose up to 1% in impregnation resin, better properties is obtained for melamine paper. Also, PVA as impregnation resin, can be offer similar quality to pure urea in the resulting melamine papers.

The objective of this work is to investigate the use of PCC, and the impact of its coating weight on paper coating. In this study, two base papers from Mazandaran Wood and Paper Industries (APC and NS), and two coating compositions with the solid content of 25% containing PCC filler (100 parts), PVA binder (14 parts) and dispersant (1 part) were used. The first composition included PCC B102 for opacity increment, and the second one PCC 9020 for the improvement of brightness. Two rod RDS14 and RDS30 were used for different coating weights. After coating, the treated samples were dried in room conditions at air temperature of 25◦C and relative humidity of 54%. Physical and optical properties of control and treated samples such as air resistance, thickness, Cobb60, brightness, yellowness, opacity and roughness were determined. In comparison to the control group, all the treated samples showed improvement in brightness, opacity, yellowness and air resistance. By the two different formulations and two rods, paper roughness was increased, and the increment of water absorption was due to capillary development in coating texture. The analysis of variances showed that the usage of PCC 9020 had considerable effect on roughness of papers. In NS papers, change of PCC caused significant difference in brightness and roughness, but in APC papers did not. The change of coating rod in APC papers had significant effect on water absorption, brightness and opacity but did not show in NS.

Antibacterial papers such as food packaging papers are important for human health. In this study, with the aim of the production of environmentally friendly antibacterial paper, nanoclay was selected as a productive agent of antibacterial effect. Since the effectiveness of nanoclay depends on the amount of its negative charge, nanoclay was homogenized using a homogenizer until be processed a homogeneous structure with more negative charge. Due to the negativity of charge of fibers and clay nanoparticles, Nanoclays was combined with starch at levels of 1, 3 and 4%, and the suspension was applied to on surface of the paper as an overlay using Auto Bar Coater. Antibacterial and physical properties of papers were evaluated. The results showed that nanoclays had a significantly effect on inhibiting the growth of bacteria and were able to reduce the growth of bacteria even at low levels of consumption. Water absorption of papers decreased and their resistance to air increased. Hence it can be said that homogenized nanoclay can be a desirable factor in the production of packaging papers with low water absorption, high resistance to air and resistant to bacterial microorganisms.

In the current study, modification of NSSC pulp broke fibers was done by forming starch polymeric multilayers, using Layer-by-Layer (LbL) layering method. After fiber slushing and preparation of pulp suspension with 0.5% consistency and conductivity formation of about 437 µS/cm, adding water solution of 1 mM NaCl, the experiments of fibers treatment were conducted to build the polymeric layers (up to 5 consecutive layers). Afterward, water retention value (WRV) of fibers was calculated in samples to evaluate the influence of this method on fibers hydrophilicity. The fibers were then used to prepare standard handsheets (60±3g/m2) and the physical and strength properties of sheets were evaluated as a function of the number of layers deposited on the fibers. The results showed that the WRV index of the fibers was improved by the LbL treatment of NSSC broke pulp fibers, due to the increase in starch electrostatic absorption. Successive variation in paper apparent density increase and paper thickness decrease confirmed the construction of starch multilayers on the surface of broke fibers. Formation of such multilayers on broke fibers has led to considerable improvement in tensile index (from 13.21 N.m/g to 30.65 N.m/g) and burst index (from 1.23 kPa.m2/g to 2.36 kPa.m2/g). Also, the prepared SEM micrographs approve the sheet web compaction and paper mechanical improvement resulted due to an increase in inter-fiber bonding.

This article aims to facilitate the use of methyl cellulose adhesive to repair paper works that its ink is sensitive to water. This research is conducted by analytical comparisons method and samples is collected by experiments related to research topics such as pH measurement, Calorimetric, infrared spectroscopy with total attenuated reflection (FTIR- ATR), the measurement of tensile strength as well measurement of The adhesive strength of the samples. The stages of this study is conducted so that the adhesive methyl cellulose at a concentration of 7% in methanol was prepared. The prepared specimens is treated under Temperature-humidity accelerated aging in accordance with standard ASTM D4714-96 no for 384 hours and under light in accordance with ASTM D6789-02 for 360 hours and Changes of color, pH, tensile strength and adhesion is investigated for them. Results showed that the samples pH is changed from 6.91 to 6.39 after light aging and to 6.06 after temperature-humidity aging. Also, Tensile strength of Samples is reduced from 0.31 to 0.23 kN per meter after light aging and to 0.24 kN per meter after the temperature-humidity aging. Also, the adhesive strength of the samples is decreased from 1.43 to 0.97 Newton after light aging and to 1.51 Newton after temperature-humidity aging.

Application of dry strength additives is regarded as a sustainable strategy toward improvement of recycle paper properties, and Bio-based materials utilization enhanced in this aspect extensively, respecting to different technological and environmental issues. In order to improving products properties, Cellulose and Chitosan as the most abundant biopolymers with unique characteristics, have been focused under ever increasing researches as natural and processed forms. Effects of the biopolymers, chitosan and nano fibrillated cellulose (NFC), individually and combined together on recycled pulp and paper properties showed that density and strength indices of paper (tensile, burst and tear), pulp drainage and retention during sheet formation improved with reduction in the material loss compared to the blank. Chitosan addition caused significant enhancement on all of the strengths, density and pulp retention and also reduction in material loss. Dewatering of the pulp suspension (CSF) was significantly improved by chitosan presence, with decline resulted from the higher addition level. The resulted developments were attributed to polymeric character, structural similarity and high bonding ability of chitosan with cellulosic fibers. Individually addition of NFC produced boost in the pulp retention, paper density, tensile and burst indices and fall in pulp freeness, material loss and tear index. Anionic nature, high specific surface area and hydrogen bonding ability of NFC were ascribed to these. Application of NFC just after chitosan as a complex mechanism in papermaking wet end not only had no increment in density and strength indices of recycled paper (except NFC 0.15%), reduced strengths in some cases. In the complex, the pulp properties were fluctuated compared to chitosan treatment, but were prior compared to nano fibrillated cellulose.

In this study, the effect of nanoclay particles and coupling agent on the physical and mechanical properties of polypropylene / waste paper composites was studied. To meet this objectives, waste paper fibers with polypropylene in 50% by weight, nanoclay (0, 2 and 4%) and coupling agent (0 and 3%) were compounded in an internal mixer at 155°C and 60rmp and the samples were prepared by injection molding. The results showed that the physical and mechanical strength of composite improved in the presence of coupling agent. As well as water absorption, thickness swelling, flexural and tensile strength and flexural and tensile modulus, were improved by increasing of nanoclay particles content, however notched impact strength was reduced. Also, study on structural behavior of composite with x-ray diffraction showed that nanoclay distributed as intercalation structure in polymer matrix, and distance between layers were increased with increasing of nanoclay particles content.

The objective of this work was to compare barrier property of biodegradable coatings on two base papers. Two different paper grades differing in structure (Kraft liner and printing & writing papers) were used. The papers are made in Mazandaran wood and paper industry. Coating materials with 30% solid content, included clay (100 parts) and cationic starch (12 parts), and they were mixed with two binders (PLA 10 parts and PVA 10 parts) for two formulations. The immersion method in both levels 1 and 2 minutes and two coating formulations were applied on papers. Then, the treated samples were dried in standard conditions of temperature (25◦C) and 54% humidity in the room. For that purpose, air resistance or porosity, thickness, mass, and Cobb60 were determined. As expected, time of treatment, reduced porosity and increased coating weight, but in terms of barrier properties, combination containing PVA was more effective than PLA. In comparison to the control group, all the treated samples had higher air resistance and water absorption, which the increment of water absorption is due to increased capillary in texture paper. The analysis of results showed that the immersion coating factors had considerable effects on performance of air resistance improvement and coating weight of papers. Then, calculated values of the thickness and density of coating were evaluated, which confirmed the status of water absorption. The treatments greatly increased the wettability of the surface by water.

The properties of catalyzed organosolv pulp obtained from maple juvenile wood were studied. The physical properties of fiber (e.g. length, width, and cell membrane thickness) and chemical composition of maple juvenile wood (e.g. average cellulose, lignin, extractives, and ash content) were determined. The variables were cooking temperature (190 and 200 ºC) and time (40, 60, and 80 minutes). Chemical charge ( 280 ml methanol, 70 ml water, and 0.025 mols of Calcium Chloride and Magnesium Nitrate) was kept constant. Pulp screen yields (54.9 to 60.91% ) and Kappa No. (15.5 to 18.4 ) were measured. Pulp freeness was reduced to 350 ml CSF in PFI mill, and ten 60 g/m2 handsheets were made from the selected pulps. The strength properties of catalyzed organosolv handsheets including tear length (3.83 to 4.25 km), tear index (10.22 to 12.81 mN.m2/g), and burst index (1.74 to 2.15 kPa.m2/g) were compared with those of the conventional Kraft handsheets of maple juvenile wood. The least allowed values of the mentioned properties in the Indian (IS) and Japanese international standards (JIS) reveal that while the tear length value is slightly below that of the standards, the values of tear and burst indices are well beyond the given standards, and the environmentally-friendly catalyzed organosolv pulping process (higher yield and lower Kappa No. compared to Kraft) can be recommended to produce paper pulp from maple juvenile wood.

Location selection for factory competitiveness in the market place plays an important role and should be chosen so that will leads achievement of the strategic advantages compared with other competitors. The objective of this study was determination of the effective criteria for decision making to select the most suitable location for establishing a fluting paper mills from agricultural residues. For this purpose, effective criteria were divided into five major groups: Material and Product, Facilities and limitations of regional (infrastructure), Technical and Human, Economical, Rules & Regulations as well as 33 sub-criteria, after preliminary investigation, preparatory observation, and an interview with some of the paper producers and relevant experts. A hierarchy was designed based on five major groups of criteria and then the priority rates of obtained criteria and sub-criteria were determined by Analytical Hierarchy Process (AHP) after compiling expert's opinions via questionnaire. Results have shown that among 33 determined effective criteria in location selection of fluting paper mills from agricultural residues , the sub-criteria of Supply residual amount, Ensure the supply of residual, Cost purchasing of raw material, Cost of transporting raw material have the highest priorities, respectively

Surface sizing of paper by anionic starch were carried out with the aim of its concentration effect on physical and strength properties of recycled paper. For this, hand sheets (100 GSM) of mixed recycled pulp containing 1% cationic starch were prepared and were treated by the sizing agent on the sheet surface at various concentration (0, 3-10%). Application and concentration increment of the starch solution caused its higher retention on the surface and lesser penetration into the paper structure (Z direction), contributed to the better hydrophobicity of sized paper and significantly reduction in water absorption of the paper, with the highest reduction in the Cobb test up to the solution concentration of 5%. Also, the results revealed that regarding to absorption and its increment into the paper surface combined to penetration to the paper thickness, strength properties of bending stiffness, burst and tensile indices have been increased which the improvement rate were more predominant up to the 5% cons. Penetration of a part of sizing agent into the porous structure of paper and resulted improvement in fiber bonding are possible and probable, that higher concentration and viscosity of the starch solution contributed to the lesser penetration and bonding formation with higher retention on the paper surface which resulted in continuous improvement in paper smoothness. With the sizing solution thickening, tear index decreased due to starch film formation on the paper surface with brittle character. In general, increasing of the anionic starch solution up to the 5% could be reported as an optimum level.

The aim of this study was to evaluate the effect of formaldehyde addition to Sodium Sulfide cooking liquor for chemical Pulp Production from rice straw. Rice straw (oryza sativa) was collected from the rice field of Salmanshahr and was carried to the laboratory of wood and paper in Gorgan University. Digestion conditions of pulp included cooking temperature of 160 °C, digestion times of 30, 60 and 90 min and useing chemical (16, 18 and, 20% Sodium sulfite and 4 and 6% formaldehyde) based on oven dry dosages weight of raw material. Four different treatments, at a Kappa number ranges of 12 - 14 were selected from each pulp In order to evaluate the effect of formaldehyde added based on Kappa number and pulp yield relations. Hand sheets with grammage of 60 g/m2 were prepared from each of pulp samples and their properties were measured using the related Tappi standard. The results indicated that the addetion of formaldehyde in sulfite liquor increased the pulp yield at the same Kappa number, accelerated delignification rate and improved delignification selectiving as well as improving the mechanical properties of paper

Several processing parameters affect the function of cellulose nanofiber as an environmentally friend cellulosic reinforcer. One of the potential parameters can be the mixing temperature of pulp and cellulose nanofiber that has been investigated in this study. In order to study the influence of this parameter, mixing drainage velocity and the air permeability and strength properties of resulting paper were measured. A mixture of chemi-mechanical pulp suspensions (with concentration of 0.2 wt% and freeness of 250 ml, CSF) containing 5 wt% cellulose nanofiber were prepared. This mixture was then stirred at 25, 50, and 70 ◦C using a magnetic stirrer for 1 hour followed by draining using vacuum filtration to make wet handsheet. The wet handsheet was first pressed, and then dried in oven at 100 ◦C for 24 hours. The test’ results showed that the increase of mixing temperature led to decreasing drainage time and air permeability. The strength properties of paper reinforced by nanofibers were positively affected by mixing temperature (i.e. the more mixing temperature, the higher strength). The data of tensile strength index was considerably increased. The tear strength of paper increased approximately by 200% over rising mixing temperature.

Theaim of this research was investigation on the performance of an electrocoagulation process with aluminum sacrificial anode for removal of TSS and COD from effluent of a paper recycling mill. The effect of electrolysis time (10, 20, 30 and 60 min), initial electrolyte pH (3, 5, 7.5 and 10), and voltage (9 and 12V) were studied on the electrocoagulation efficiency. Increase of voltage from 9 to 12 V caused significantly removal of TSS and COD whichthe highest removal rate at 12 voltages for TSS and COD were 99%, and 77%, respectively, while the values for the same parameters at voltage 9 were 97% and 33%. The results also show that the initial pH of effluent has a key role in process efficiency so that in neutral limit the TSS and COD removal was more than the other pHs. It can be concluded that EC technique can be used as a simple and efficient method for treatment of paper recycling mill effluent and thereby pollution reduction.

In this research, the quality of recycled OCC pulp collected from different local companies was investigated compared with those of the local NSSC pulp from Mazandaran Wood and Paper Industries(MWPI). Also, the effect of different mixture from OCC pulp was evaluated with NSSC pulp. In addition, the effect of refining was studied on strength properties of OCC pulp and also combination of OCC and NSSC pulp. The results showed that, the NSSC pulp has the better fiber classification properties and higher strength properties compared to the recycled OCC pulp. Also, quality of OCC recycled pulps prepared from different companies was different because of the variety of raw material and production process. Refining of OCC pulp led to increase the mechanical properties of paper. The results of the handsheets and fluting papers prepared with various charges of OCC recycled pulp show that the majority of the mechanical properties were decreased and only tear strength were increased but difference between strength values were not shown significant. Totally, the results showed that by installation of an independent OCC mill in Mazandaran Wood and Paper Industries (MWPI) or completing present stock preparation with cleaning and suitable refining system, there is possibility to increase OCC consumption for fluting production with desirable quality.

Studying and rating of oncoming challenges of the wood and paper industries of the country can create a delicate attitude for policy makers and investors of these valuable industries. This study by the aim of identification and evaluation of wood and paper industries challenges with scientific and authentic method of likert spectra scale was done is 2010. Present challenges of wood and paper industries were detected by literature review and consulting with experts and academician and a number of manufacturing unites of wood and paper industries and query was designed. Intended data and statistics obtained from experts of wood and paper industries were compared and analyzed by likert scale spectra. The results showed that of 24 examined challenges, shortage of raw material, lake of long, compressive and applied prospective, existence of great gap between the university and industrial units and wearied and aged machinery are among the most important. Finally the identified challenges were submitted to the authorities for helping the economy of the country as well as causing the prosperity and budding of these industries.

Important importers of wood, paper and their products were identified in this study. Identification of these countries is important for the trade of wood and paper products. The main questions now are: how is imports situation of wood, paper and their products in the world? And which countries are important here? Average values and percentages of imports were calculated to rank regions on the basis of FAO stats from 1998 to 2007. The annual rates of change in imports were calculated by single payment formula and the positive correlation of import prices was determined by coefficient of determination. Our results showed that imports of products frequently had increasing trends in the study period, and they had stable markets with low fluctuations. China and Germany were the most important countries with France, Italy, Japan, Canada, Belgium, Holland, Austria, South Korea, Mexico and Denmark ranking next for these products. Wood and paper products of Asian countries were developing faster than other continents. Import efficiency of paper and wood products of Iran is low due to their high added value. Political developments after 2001 and increasing energy prices resulted in increase in products price worldwide with trends being increasing with high coefficients of determination (R2).

Unbleached Kraft pulp made from poplar chips, Pre-treated by Trametes versicolor in 1, 2 and 3 weeks (Bio-Kraft pulp), was used as raw material in this study. Mentioned pulp after each step of bleaching, in ECF method at DED sequence, characterized in the lignin content, and effective groups on the brightness reversion (Carbonyl, carboxyl and Hexenuronic acid). In order to evaluation of brightness reversion, 60 g/m2 standard handsheets made from above pulps treated in thermal and UV ageing and then measured its brightness. Results showed that by increasing in pre-treatment time, in all bleached treatments, lignin content increased excluding D1 step in 3-weeks pre-treatment; Carbonyl groups was the lowest content in 1-week pre-treatment (third step) and 2-weeks pre-treatment (first step) and carboxyl groups and hexenuronic acid decreased after 3 step sequence bleaching. Effect of thermal pre-treatment ageing on brightness reversion considerably more than UV treatment. Also, paper from pre-treated chips in 1 and 2 weeks had minimum brightness reversion and paper from 3-weeks fungal pre-treatment chips had maximum brightness reversion due to more carbonyl and Hex-A. In this respect, 2-weeks pre-treatment time confirmed for fungal pre-treatment.

In this research, different additives of cellulose nanofibers, cationic starch and polyacrylamide to bagasse pulp and their impact on the handsheet strengths were investigated aiming to replace with imported long-fiber softwood pulp in Pars paper factory. For this purpose, first 3% bleached bagasse cellulose nanofibers, 3% unbleached nano-lignocellulosic fibers, 0.5, 0.7 and 1% cationic starch, and 0.03, 0.05 and 0.1% cationic polyacrylamide were added separately to bagasse pulp. In the next stage,3% bleached bagasse cellulose nanofibers and 3% unbleached nano-lignocellulosic fibers along with 0.5% cationic starch or 0.05% cationic polyacrylamide were used. The results showed, adding nano-cellulose fibers along with cationic polyacrylamide or starch have increased handsheet strengths significantly. Yet, the best treatment was the addition of 3% nano-lignocellulose along with 0.5% cationic starch which resulted in the higher tensile and burst strengths and lower tear and fold strengths than that of adding 12.5% long fibers to bagasse pulp. So that, comparing with paper made from pure bagasse pulp it showed the increase of 16.57% in tensile index, 8.47% in burst index, 9.77% in tear index, and 168.85% in folding strength.

Considering the growth in population, the need for wood consumption also increases. The rapid progress of science and technology doubles the wood consumption. Supplying this need at a glance was focused on the forests. Forests for many reasons have faced decrease in production and this extreme need for wood, by planting fast growing trees (poplar, eucalypt, Paulownia …) makes it possible. One of industries plenty of the wood is paper industry that needs to huge primary wood material. This industry can continue their production activities by using the wood of poplar. This research was found out with the aim of assessing the practical characteristics of poplar wood by nondestructive test method in paper production industry. Poplar sites were selected in areas of country that poplar trees were planted widely. For locating the production of different site in paper industry found out Analytic Hierarchy Process (AHP) in Expert choice 11 software. For field studies of this research, the questionnaires were prepared and sent for expert and university professors with special expertise in this industry. The results showed that: Production of Pulp and paper industry: in this industry among of five main indexes influencing in pulp and paper production, fiber morphology trait recognized as first priority with weighting value (0.435). Production allocations with their weighting value are determined: Sari (0.240), Fouman (0.236), Lashtnasha (0.182), Abhar (0.174) and Zanjan (0.168), respectively.

Increasing use of wood products accompanying with resource constraint has revealed the importance of nonwood based material. In this study, pulping and papermaking potential of three varieties of weeds including Xanthium spinosum, Carthamus tinctorius and Cyperus papyrus have been considered. At first, chemical components of the samples i.e. cellulose, lignin and extractives have been measured following TAPPI standard test methods. Afterwards, pulping process based as soda and Kraft has been carried out and the pulp properties i.e. screen yield and reject, kappa number, caliper, bust index, tear index, brightness have been considered. According to the results, the amount cellulose, lignin and extractives have been measured for the Xanthium spinosum %38.15, %13.5 and 4.72, respectively. Theses parameters have been estimated about %38.25, %10.3 and % 2.95 for Carthamus tinctorius and %38.8, %19.2 and 4.4 in case of papyrus. The yield of soda and Kraft pulp of the papyrus was more than Xanthium spinosum and Carthamus tinctorius. Among all treatments, the highest screen yield related to soda pulping of Cyperus papyrus by %39.8 which has been obtained by 175 centigrade as a maximum temperature, L/W: 6/1, active alkaline: %30 and 90 minutes as the time at temperature. The lowest and highest amounts of the tear index were related to soda pulp sample of the Carthamus tinctorius and Kraft pulp sample of Xanthium spinosum by 2.49 and 8.1, respectively. In addition, the lowest and highest amounts of the bursting index were related to soda pulp sample of the Cyperus papyrus and Kraft pulp sample of Xanthium spinosum by 0.61and 2.48, respectively. Meanwhile, soda pulp sample of the Cyperus papyrus showed the highest amount of brightness with %45 ISO.

This study aimed at evaluating effect of sizing agent and various fillers on properties of printing and writing paper. Therefore, sizing agent (AKD) in 1.5% level and fillers including precipitated calcium carbonate (PCC), ground calcium carbonate (GCC) and Obtained from Water Treatment Process (SCC)in 30% level were applied based on dry weight of fibers in furnish consisted of 80% chemical-mechanical pulp (CMP) of hardwood and 20% bleach softwood kraft pulp (BSKP) according to TAPPI Standard. In order to investigate the effect of sizing agent and various fillers, papers with 60 g/m2 basis weight were produced from each treatment. Results showed that the dimensional properties of calcium carbonate species is effective on strength properties of paper. Of the three types of ground calcium carbonate (GCC), precipitated (PCC) and softening calcium carbonate (SCC), precipitated calcium carbonate due to smaller particles cause a further reduction in paper strength and Calcium carbonate from water softening due to the larger particles, had a minimal impact in reducing the paper strength properties. Paper filled with precipitated calcium carbonate has an intermediate strength properties of paper filled with precipitated calcium carbonate and softening calcium carbonate.

Surface properties of cellulosic fibers can be modified by Layer-by-Layer (LbL) technique. Cotton fibers are one of important non-wood and industrial cellulosic resources in the world. Cotton linters is produced as a by-product accompany with cotton fibers which is used as a significant cellulosic sources in paper industry for producing durable paper. In this research, the influence of alternate adsorption of cationic chitosan and anionic Nanosilica on modification of fiber surface of cotton linter was investigated. The adsorption of materials on cellulosic fibers was analyzed via electrolyte titration. Experiments were conducted at pH≈3-4 for formation of cationic layer and pH≈9-10 for formation of anionic layer applying stirring rate of about 750rpm, for15 minute deposition time to construct 1 to 3 layers. Hand sheets of about 60 g/ m2 basis weight were made form modified pulp fibers prepared by multilayering of chitosan and nanosilica, then their structural properties and bonding ability were evaluated. Bonding ability of fibers was improved by polyelectrolyte multilayering (PEM) on the surface of cotton linter fibers which was visualized by Field Emission Scanning Electron Microscopy (FESEM).The results showed that apparent density and also bonding ability was improved in the treated fibers because of the increased electrostatic attraction between polycation and anion sites existed on the fiber surface. Apparant density of paper was improved remarkably compared to the untreated fibers. Tensile index of the sheet was increased about 16% with consecutive adsorption onto the cotton linter fibers compared to untreated fibers. Formation index of paper was slightly deteriorated after polyelectrolytes multilayering.

Sandwich panels are new kind of layered composites that usually are composed of three layers and their core layer's thickness is higher and the outer layers are determinative in determination of the products strength and stiffness. The core layer is commonly made of honeycomb paper, corrugated paper and polyurethane etc. In this study, effects of face and adhesive types on mechanical properties of sandwich panels made from honeycomb paper were investigated. The variables included three types; beech face, poplar face and hardboard (S2S face, veneer less) and adhesive type (two types; epoxy and PVA). Out of experimental panels specimens were cut and tested according to DIN E 326-1 standard. Mechanical properties of panels, included modulus of elasticity as well as modulus of rupture at the edge and surface (based on DIN EN 310 standard) and Impact Bending Strength (IBS) of the panels (based on ASTM D 3499 standard) were measured. The gathered data were analyzed as completely randomized factorial design. Highest mechanical properties were reported for panels glued with epoxy resin and containing fiberboard at the middle. According to results, optimum condition of producing sandwich panels was observed in uses of epoxy resin and fiberboard S2S face, veneer less) at the middle.

In this study, the effect of enzymatic refining with endoglucanase was investigated on the physical and mechanical properties of OCC pulp. Collected OCC pulps were pre-treated with different endoglucanse dosages (1u, 2u and 3u on o.d. pulp) under constant conditions and then refined at different levels. The effect of different enzyme dosages and refining levels were evaluated separately on the paper physical and mechanical of properties, as compared to control pulp (non treated pulp with enzyme). In unrefined pulps, the results have shown that adding enzyme up to 1u caused to improve the physical and mechanical properties as significant (confidence level of 95%), compared to control pulp. However using more than 1u endoglucanase resulted in a significant decrease in both physical and mechanical properties. Achieved results from the effect of different enzyme dosages and refining levels showed that in refined pulps, increase of enzyme level caused to produce a bulky paper and decrease of mechanical properties. In general, the best physical and mechanical properties were obtained using 1u endoglucanase at different refining levels applied.

In this study the effects of oxidative bleaching and mechanical dispersion in different conditions on the optical and mechanical properties of deinked recycled pulp was investigated. Industrial deinked pulp was treated in the different conditions, including dispersion, combined oxidative bleaching during dispersion, and separate dispersion and then oxidative bleaching. Handsheet papers were made from obtained pulps and then scanned and taken photos were analyzed by Digimizer software, version 4.1.1.0 to analysis spot content. Optical and mechanical properties of obtained handsheets were determined and compared. Results indicated that mechanical dispersion decreased spot content and brightness and increased yellowing of the handsheets. Moreover, mechanical dispersion increased dry and wet tensile and burst strengths, water retention value (WRV), ash content and decreased tear strength of handsheet papers. This study revealed that combined dispersing and oxidative bleaching of de-inked pulp provided superior results in comparison to the separate dispersing and oxidative bleaching.

Nowadays there is a great competition for the production of packaging paper from recycled fibers. But success in this competition depends on improving its strength properties. Thus when it comes to talk about recycled fiber, the first and most important challenge is to tailor it for pulp and papermaking. Quantitative and qualitative papermaking information of recycled papers will significantly help to achieve this objective. Therefore in current research, some of papermaking parameters such as: fiber length average and distribution, the kind and amount of pulp and also the existing quantity of starch in OCC pulp were studied. The results showed that its fibers length has uneven distribution and more than 85% of OCC fibers have the average length less than 1 millimeter in the range of 0.47-0.65mm. Undoubtedly, this uneven fiber length distribution and its low length average would decrease the strength properties of paper. Fiber staining analysis applying Graff ″C″ stain represented that main section of fibers approximately 72.91% is from kraft pulp, and mainly softwood resources (33.33%). Moreover, the amount of extracted starch was measured nearly 2.32±0.25%. It should be considered that in recycling process, this amount of starch can strongly affect the chemical charge balance in wet end section of paper machine.

The last two decades consisted of a steady decrease in timber production levels in Iran in order to preserve the Hyrcanian forest as the only source of industrial wood. Consequently, under the so-called “the Forests’ Breathing Plan” in 2017 the Islamic Parliament of Iran stipulated that any wood exploitation from Iranian forests will be prohibited beginning in 2020. In order to respond to increasing wood demand and the cessation of the domestic production of natural-forest wood, the future prospect for the production and trade of wood commodities must be assessed. The main objective of this study was to predict the monetary values of domestic production, imports, exports, and prices of wood products in Iran through 2030 under the Forests’ Breathing Plan. The assessment was performed using the Global Forest Products Model (GFPM) and for three categories of wood products: unprocessed wood, semi-processed wood products and pulp and paper. The GFPM is a partial equilibrium model that forecasts wood demand based on the growth rate of gross domestic product in each country and predicts price by establishing equilibrium between demand and supply. The results indicate that the growth of domestic production will be larger for the second category of wood products than for pulp and paper. The import of unprocessed wood will reach nearly USD 200 million in 2030 and the production and import values of semi-processed wood products will increase 2.2 and 2.6 times, respectively, compared to 2015. Nevertheless, the total trade balance of wood products will deteriorate by 91% for Iran. Compared to pulp and paper, the increase in the price of the unprocessed and semi-processed wood will be greater. Overall, the global position of Iran’s trade and production of wood products will not improve significantly except for the import of unprocessed and semi-processed wood during the period examined.

The purpose of the present research is enhancing the thyme essential oil efficacy by microencapsulation technique with emphasis on controlled released mechanism. First, essential oil was extracted by hydro-distillation in a Clevenger-type apparatus for 4 h. Then, core-shell microcapsules were prepared using solvent evaporation method with oil in water emulsion system. To measure the efficacy of encapsulated thyme oil, UV-visible spectrometer was used and was found to be 67 percent. The size and shape of oil droplets in emulsion were observed with optical microscope and the morphology of the polymer capsules was observed with scanning electron microscope. Release kinetics in both free and encapsulated forms showed that all components of free oil evaporated into atmosphere, while just 6 percent of capsules evaporated in the same condition. So, microencapsulation method increased the efficacy of the essential oil with controlled release mechanism. Filter paper disk test was performed to investigate the fungicide effects of thyme oil in both free and capsulated forms before and after leaching test. Results revealed that there are no significant differences between control samples and those treated by free oil especially after leaching test. In contrast, the samples treated by microencapsulated thyme oil showed much more resistance against Aspergillusniger mold indicating that the controlled release mechanism can prevent mold growth on filter paper disk and therefore improved the oil efficacy.

In the present research , the effect of utilizing a mixture of Birch with Hornbeam & Beech species (in the comparison with sample CMP( 75% Hornbeam 25% Beech) , on the mechanical and optical properties of papers produced within the domain of Freeness degree (CSF) of 300 ml and 85% yield has been reviewed . The CMP was prepared in accordance with 85% yield condition , different cooking times (30-120 min) , temperature of 170°C and white liquor ratio to chips in 7 to 1 & 20% Sulfide based on chips dry weight at 4 levels of 10, 20, 30 & 100% Birch mixed with Birch and Hornbeam species. After defibration and preparation of 60gm hand sheets, the optical and mechanical properties of that were assessed. The results indicated that by increasing the percentage rate of Birch , the quality of the manufactured paper was also increased and the best strength and optical properties were related to the 30 & 100% consumption rates of Birch in mixture with Beech and Hornbeam species.

Extraction and purification matairesinol bioactive lignan of arizonica cypress (cupressus arizonica) A. Sedaghat1, A. Abdulkhani 2 1. M. Sc, Department of wood and paper science, Faculty of Natural resources, University of Tehran 2. Assistant Professor, Department of wood and paper science, Faculty of Natural resources, University of Tehran Matairesinol lignan (MR) of arizonica cypress was isolated, characterized and purified. Isolated was made using a hexane pretreatment for removing the lipophilic moieties followed by an ethanol-water (9:1 v/v) treatment by soaking the wood flour in the solvents. Also matairesinol, was purified with potassium acetate. Identification of extracts were performed in all stages by means of gas chromatography- mass spectrometry (GC/MS). Results showed that amount of MR lignan in the original ethanol extract, sediment and clear solution after centrifugation was 11.3, 32.59 and 40.44% respectively.... ...... .... .... .... .. ..... .... .... ... .......................................................................................................................... ......... .............................. ..... ...................................................................................................... Keywords: arizonica cypress, gas chromatography- mass spectrometry (GC/MS), wood knot, lignan, matairesinol (MR), extractives

In this research, the effect of enzyme treatment to modify bagasse soda pulp properties was investigated. Viscozyme enzyme (mixture of carbohydrates degrading enzymes) extracted from fungus Aspergillus aculeatus was added to pulp at different dosages of 0.5, 1 and 2 IU (based on per gram of oven dry pulp) and reaction times of 0.5, 1 and 2 hours. Tappi standard was used for preparation handsheets. For comparison handsheets from analysis of variance test and for comparison of the means from Duncan test were used. The results showed that pulp freeness and polymerization degree of pulp decreased as enzyme dosages and reaction times increased. In fact, enzymatic pretreatment by partial fiber fibrillation played the role of a refiner and improved mechanical properties of paper. Enzymatic treatment improved tensile and burst index. Enzyme concentration of 0.5 IU and 1hr reaction time had the most effect on tensile and burst index. Although higher enzyme concentrations (2IU) decreased strength properties of paper due to declined viscosity, but in comparison with control sample had more strengths.

The utilization of tree branches as potential resource of fibers, that can be supply raw materials for pulp and paper industries, additionally, increases the productivity of tree. This research was done in order to compare pulp and paper properties from branch wood and stem wood and feasibility utilization that in pulp and paper industries. Stem and branch wood samples of hornbeam with mean diameter about 15 cm were obtained from Shastkolateh educational forest (Gorgan).The measurement of fibers was done with using Franklin method and light microscopic and chemical compositions were determined according to TAPPI test methods. The Kraft pulps from stem and branch wood were prepared under constant condition include sulfudity 20%, Max temp 170˚C and Liquor to wood ratio 5/1 and variable condition include active alkali 14%, 16% and 18%, and cooking time of 90, 120 and 150 min. Ultimately mechanical properties of Handsheet were measured according TAPPI test method The statistical analysis of results indicated that independent effects of wood, active alkali, and time were significant on pulp yield and Kappa number. Comparing the pulp yield and Kappa number means were showing that yield of stem wood pulp is higher than branch wood and its kappa number is less. Analysis mechanical properties on stem and branch wood Hand sheets showed that mechanical properties of Hand sheet from stem wood are higher than branch wood. There is none meaningful difference between the most mechanical properties hand sheets of stem and branch wood, that produced under cooking condition include sulfudity 20%, active alkali 18% and cooking time 150 min. therefore this condition would suggest for simultaneous cooking branch and stem wood

To study the possibility of using plant Silybum marianum in paper industry, its stem yield potential, chemical properties, fiber indices and pulping was evaluated. Mean value of fiber length and diameter of Silybum marianumstem harvested in early June, were calculated 178 and 3.5 cm, respectively. Dry weight of whole stem determined 4710 kg per hectar. Mean value of fiber length, diameter, cavity diameter and wall thickness were obtained 1194, 16.06, 9.06, and 3.66 μm, respectively. Raunkel, flexibility, and slenderness ratios of its fibers were determined 80.83, 56.39, and 74.37, respectively. Results of chemical analysis showed that the stem comprises %70.35 holocellulose, %39.25 cellulose, %13.13 lignin, %3.09 acetone-soluble, %18 hot water-soluble extractives, and %11/85 ash. Soda pulp was obtained at 165 °C pulping time, 25% alkaline and 10:1 ratio of liquor to chips. Results of pulping showed that with increasing of pulping time from 30 to 210 minutes, the kappa number and yield decreased from 77.32 to 32.13 and 43.6 to 36.5, respectively; whereas accepted pulp yield (passed from 20 mesh) increased from 17.4 to 35.5% paper made of pulp with kappa number 32 had 36.82 Nm/g tensile index, 3.76 km breaking length and 1.75 Kpa.m2/g burst strength. In general, achieved results have shown that the present studied species could be regarded more for papermaking because of the suitable fiber biometrical and chemical properties as compared to other non-woody plants.

Old Corrugated Container (OCC) recycled pulp provided by a local paper manufacturing company was treated by lactase enzyme. The pulp was sampled from headbox and treated by enzyme in the conditions of consistency 2%, pH 5, reaction time 2 hours, and reaction temperature 60 °C in dosing levels of 0.005, 0.01 and 0.015 % based on oven-dried weight of pulp. Fiber classification of the control pulp showed 31.3 % of fines content and 0.82 mm average fiber length. Results have indicated that lactase treatment decreased kappa number and SR degree to 20% and 14 degrees, respectively which consequently facilitated the drainage of pulp. The extraction of treated samples showed a peak at around 280 nm, confirming the delignification of pulp by enzyme. Microscopic observation of fiber walls of the treated sample indicated a local separation of middle lamella, fiber linting and removal of fines from fiber surface. The highest Water Retention Value (WRV) was measured to be at 0.015% enzyme addition level. The apparent density of handsheets made from treated samples was lower compared with the handsheets made of control pulp resulting in loss of paper strengths.

This research was carried out in order to comparatively investigate the hornbeam kraft, soda and soda-urea papermaking properties. The selected treatment in kraft process had an average yield of 44.43% and kappa number of 23.75. In soda process the selected treatment had an average yield of 38.75% and kappa number of 19.28. In soda-urea process, the selected treatments had an average yield of 39.85, 40.1, 40.5, 39.8 and 40.61 and kappa number of 21.21, 22.33, 22.66, 25.28 and 26.85. After refining the selected pulp to reach the freeness of 400±25 ml CSF, 60 g/m2 handsheets were made and physical, mechanical and optical properties were measured. Results showed that kraft pulps had higher yield and better refinability than soda and soda-urea pulps. Papers made from kraft process had higher strength properties than those made of soda and soda-urea process. With addition of urea, yield and kappa number of pulps increased. The highest improvement in tensile index, breaking length and tear index was achieved with addition of 3% urea and the highest improvement in burst index was achieved with adding 4% urea. Results of brightness measurements showed that papers from kraft and soda processes had the lowest and highest brightness degree respectively. With the addition of urea, brightness of papers decreased.

This paper investigated the radial variations of acoustical and mechanical properties of date palm from the pith to the bark. Cubic samples with dimensions of 2×2×35 cm3 (Radial× tangential ×longitudinal)) were taken in distance of 3, 6, 9, 12 and 15 cm toward the bark. To evaluate dynamical properties of date palm, flexural vibration method was applied on cubic experimental samples. Further the specimen then were utilized for measuring MOE and MOR in static bending test. More details were also attained by anatomical analyzes. The results showed that the acoustical parameters of the propagated wave (the internal friction, the acoustic conversion efficiency as well as the acoustical impedance) were constant while increasing the distance between pith and bark. The highest values of acoustic coefficients found for samples near the pith and partially increased while moving to the bark. The density variations were less important in radial direction of date palm disk. The MOE and MOR values significantly radially varied and were maximum for samples in distance 3 cm. As they reached to the distance of 15 cm from the center, the given parameters dramatically decreased. Finally it can be conclude that the quality assessment of date palm based on the acoustical parameters is not reliable. It is suggested to provide samples from the outer parts of date palm disk when construction materials need more strength.

Enzymes are protein molecules with complex structures that accelerate the biochemical reactions. Activity of these chemical compounds is accomplished at limited range of pH, temperature and concentration. In this study, the effects of different concentrations of cellulose enzyme were investigated on deinking of old newsprint. Old newsprint (ONP) was repulped at 5% consistency for 10 minutes in disintegrator with total revolution number of 26500. Enzymatic treatments of recycled ONP pulp were done under constant conditions (10% consistency,treatment time of 15 minutes, pH range of 5-5.5) at different cellulose concentrations of 0.025, 0.05, 0.1 and 0.2% (based on oven-dry waste paper). The optical and physical properties of the standard paper (60g/m2) made at different concentrations of cellulose were evaluated in comparison with control pulp (untreated ONP pulp with cellulase). Overall, the results achieved by comparison the optical properties of the paper produced indicated that using cellulase in deinking of ONP led to increase the brightness and the yellowness and decrease the opacity. The brightness was improved to a maximum level of 47.5 ISO %, but the yellowness was decreased to a minimum level of 11.3 ISO %, while the brightness reduced and the yellowness increased at higher concentrations than 0.05% cellulase. The highest opacity of 99.3 ISO % was achieved using 0.1% cellulase even higher than control pulp. The results gained by comparison the physical properties of the paper showed that using cellulase resulted in decrease of paper calliper, air resistance and density and improve the freeness of pulp

This study was aimed at determining the effective criteria for location selection of WPC Plants from agricultural residues in Iran. For this purpose, after review and studies papers and books, Six criteria" products and materials, regulations, technical and human, economic, infrastructure and environmental and also 30 sub-criteria were identified. The priority rates of these criteria and sub-criteria were evaluated by AHP technique. The results indicated that among 30 effective sub-criteria in location selection of the WPC plants from agricultural residues, amount of wastes supply (0.087), continuity of wastes supply, cost of wastes supply, amount of sales and export, granted facilities and less Hazards for the environment and forest had the highest priorities, which were rated as 0.071, 0.067, 0.065, 0.064 and 0.062 respectively.

Athel tamarisk (Tamarix aphylla) is a fast growing, evergreen tree succeeding in the most soils and can tolerate the saline conditions. Despite its ecological importance and wide distribution in central and southern parts of Iran, wood properties of this species has little been concerned. However, the potential of this species in cellulosic industries of Middle East dry countries has recently been focused. Hence, to study wood anatomy and physical and chemical properties of Athel tamarisk, 3 stands were selected and felled from the Zabol region (Sistan and Baluchestan province). Wood anatomical features of this species were studied and listed according to the list of microscopic features for hardwood identification by IAWA Committee. In addition, lignin distribution in xylem was studied using fluorescence microscopy. Calculating fiber biometry features assessed that although fiber quality is not perfect but meets the standards of paper production, comparing other commercially used hardwoods in this industry. According to chemical composition analysis, cellulose content of this wood is rather low (39%) which could be a result of large amount of thin-walled paranchyma cells in xylem. Lignin content is a bit higher than average hardwoods and this component is concentrated in vessels and fibers. Physical properties of studied wood samples (specific gravity and shrinkage values) were in the range of other light-weight and fast growing hardwoods and thus this wood is expected to have similar end-use quality.

Carboxymethyl cellulose (CMC), one of the most important cellulose derivatives, is widely and increasingly used in industries as emulsifier, stabilizer, disperser, thickener, and gelling agent. The main raw material of the cellulose derivative is cellulose from wood and cotton linter. However, lack of the fiber resources, especially in Iran, gradually grown interest on other available fiber resources such as agricultural waste and recycled fibers, as alternative cellulose resources. Bagasse pulp as a non-wood fiber and mixed office wastepaper deinked pulp as a recycled fiber were carboxymethylated in aqueous alkaline medium using mono chloro acetic acid (MCA) as etherifying agent under identical conditions. Then, this paper explores the production feasibility of carboxymethylcellulose (CMC) from the unusual pulps combined with the comparison. The chemical composition of the pulps were determined; include α-cellulose, hemicellulose, lignin, extractives and ash content, water retention value, intrinsic viscosity, carboxyl group and pH. α-cellulose content as the most important character of the derivatization was 84.66% in DIP and 71.33% in bagasse pulp. DIP non-polysaccharide compound (lignin, Ext. and ash) was 5.92% compared to 2.36% for bagasse pulp. Cellulose carboxymethylated were done and the degree of substitution (DS), viscosity, purity, pH and yield of the prepared CMC was also determined and found to be dependent upon the source of the cellulose pulp. Viscosity and purity were higher in CMC produced from DIP (981 cPs and 93%, resp.) compared to the bagasse pulp (680 cPs and 87.33% resp.), which is attributed to its originally higher α-cellulose content. Yield and D.S were higher in CMC prepared from bagasse (168.8% and 0.57 resp.) compared to DIP (155% and 0.45 resp.), which are originated from lower crystallinity and molecular mass compound in bagasse, resulted in higher substitution of carboxymethyl groups.

In this paper a new method is introduced for defect detection in veneer images to investigate wood quality. In this method firstly, separating of defects from natural background of veneer is modeled a hypothesis testing problem. In the next step, the natural texture of veneer is eliminated by using morphology concept. Finally the correct boundaries of defects are extracted by optimizing energy function on above homogen area. Performance of the proposed algorithm is evaluated on real captured images containing several kinds of surface defects. The results demonstrate that the proposed method detects the defects approximately 18% better than some present approaches. Furthermore, it may be shown that better detection of defects in the proposed algorithm not only does not lead to extracting more false defects, but also it decreases rate of false detections approximately 8.2% compared to the existing algorithms. Consequently, it may be concluded that the proposed method may be used as a suitable alternative for detecting defects in veneer surfaces.

Due to the size and importance of poplar culturing and its role in the West Azerbaijan province economy, evaluation of the poplar value chain is necessary. With drawing up a comprehensive value chain and identify the lacks, setting the value chain in the province were studied. Finally, due to lacks of the value chain, value chain strategy for development was identified using ANP. The results of the calculation of location quotient in the West Azerbaijan province showed that the LQ is equal to 0.65852. Due to its lower LQ than one, it can be concluded that the poplar costumers in Western Azerbaijan province are less than the country average. The results of the prioritization of criteria affecting poplar value chain development in West Azerbaijan province indicated the most important criterion is the access to wooden raw materials weighing 0.16. After that the stable supply of raw materials, machinery and equipment, manpower, proximity to local markets, expertise and financial resources are with weights, 0.132, 0.123, 0.116, 0.105, 0.102 and 0.07 respectively. The weights of the other criteria have a little importance in the development of the poplar value chain. Final results of alternatives prioritization showed, the maximum weight is related to particleboard with the 0.295. The following options are OSB, MDF and HDF which have a weight of 0.185 and 0.178 respectively. After the composite wood products is turn of chemical products, namely cellulose, pulp and paper weights 0.112, 0.1 and 0.066 respectively.

In this study chemical composition, fiber biometry, pulp and paper characteristics from Criptomeria japonica wood which has been planted in Gilan province (Pisseson region) were investigated. Mean value of specific gravity and basic density of wood were 0.376 and 0.338 gr/cm3, respectively. Also, fiber (tracheid) dimension including fiber length, fiber diameter, lumen diameter and cell wall thickness were determined at 2920, 41.23, 32.57 and 4.41µm, respectively. The chemical composition of Criptomeria japonica wood including αcellulose, lignin, extractives and ash content were analyzed. On average Criptomeria japonica wood has 48.35 % cellulose, 32.08% lignin, 0.988% ash and 5.64% extractives. The results of this investigation show that on average Pulp yield was 50.53 totally. With increase in effective alkali from 12% to 18%, pulps yield decreased and show significant differences at 1%. Breaking length of hand sheets made at 12%, 14% and 18% effective alkali were 7.36, 7.17 and 9.14 Km, respectively. It was also observed that burst strengths of hand sheets made at 12%, 14% and 18% effective alkali were 4.87, 4.93 and 6.19 Kpam2/g respectively.

The main purpose of this work is to provide an overview of recent research in the area of cellulose nonmaterials production from different sources. Due to their abundance, their renewability, high strength and stiffness, being eco-friendly, and low weight; numerous studies have been reported on the isolation of cellulose nanomaterials from different cellulosic sources and their use in high performance applications. This work covers an introduction into the nano cellulose definition as well as used methods for isolation of nanomaterials (nanocrystals) from various sources. The rod-like cellulose nanocrystals (CNC) can be isolated from sources like wood, plant fibers, agriculture and industrial bio residues, tunicates, and bacterial cellulose using acid hydrolysis process. Following this, the paper focused on characterization methods, materials properties and structure. The current review is a comprehensive literature regarding the nano cellulose isolation and demonstrates the potential of cellulose nanomaterials to be used in a wide range of high-tech applications.

The aim of this paper was to evaluate relationship between dynamic modulus of elasticity (MOEd) in healthy standing trees of Populus deltoides and static modulus of elasticity (MOEs) of sawn lumber from the same standing trees, using nondestructive stress wave testing (NDT). For this purpose, NDT stress wave technique was used. The study was performed on 10 healthy standing trees of Populus deltoides. The diameter of trees at the breast height was selected at two categories, namely 25-30 cm and 30-35 cm. Measurement of wave velocity in standing trees were done transversely in radial direction at two geographical directions as North-South and East-West at the breast height, namely 130 cm and longitudinal measurements were done on the height between 80 and 180 cm. Then, standing trees were cut following by measurements of wave velocity in their logs. Logs were kept for two months after cutting in order to reduce moisture content. Then, they were cut into the clear specimens for statistical bending test and their MOE were evaluated according to ASTM standard. The results showed that the stress wave velocity and dynamic modulus of elasticity in longitudinal direction of standing trees and logs were more than those in transverse directions. Also, stress wave velocity and dynamic modulus of elasticity of the logs were higher than those in their standing trees at both directions. Finally, regression analysis indicated that the correlation coefficient between MOEd in standing trees and logs at diameter 30-35 cm is (r= 0.94), which is statistically significant.

Pre-extraction of hemicelluloses prior to pulping allows co-production of pulp and different hemicellulose-based chemicals in the chemical pulp mills. Due to important impact of hemicelluloses on pulp properties, their pre-extraction would be carried out in controlled conditions to minimize adverse effects on pulp properties. In this study, we focused on the effect of dilute acid pre-extraction on soda pulping and paper properties of bagasse to determine the optimum conditions for hemicelluloses extraction. The pre-extracted with dilute sulfuric acid was performed with 1, 2 and 4% of sulfuric acid concentration (w/v), liquid-to- solid ratio of 5, at 120, and 140 and 160 °C for 5, 10 and 15 minutes. Then, untreated and treated bagasse at selected condition were used to produce soda pulp with 11, 14 and 17% active alkali and then the selected pulps were bleached in ECF sequence. The pre-extraction results showed that dilute acid pre-extraction by 1% H2SO4, at 120 oC for 60 minute provided the best results regarding to extraction yield and residual holocellulose. However, screen yield, bleaching yield, tensile and burst strengths of obtained pulp from extracted bagasse were significantly lower than that obtained from unextracted bagasse, presumably due to considerable extraction of hemicelluloses.

Cellulose fibers undergo a series of irreversible changes i.e hornification when exposed to cycles of wetting and drying. In this study, the effect of recycling on physical and chemical properties of chemimechanical pulp (CMP) and neutral sulfite semi-chemical (NSSC) pulp was evaluated. The pulps were recycled three times. Hornification was measured by Water retention value. The results indicated that water retention value and carboxyl groups were decreased due to recycling, hornification also increased during cycles of wetting and drying. Changes in crystalline structure of the pulp during first cycle of recycling were investigated by ATR- FTIR. The crystallinity index increased to some extent, when compared to virgin pulp. Recycling influence on the fiber length was not significant. Hornification introduced as a main cause of poor properties of recycled paper. Also, reduction of carboxyl groups could be one of the causes for lowering water retention value and decrease in strengths.